2d plot with colormap behind

I am trying to make a colormap behind a 2d plot. It currently works for when the function which is represented by the line in decreasing but doesnt work for when it is increasing and vice versa for the unfolded/general case. I also sometimes get an artifact with some cases as it a function at the top of the plot where i have a blue section that should be yellow. The middle plot of the unfolded show that.

function y1_ss_param = steadystate2d_vsparam(params, params_values, expressions, variables, values, labels, tot0_value, threshold, lam_sig, sig)

figure;
original_var = variables;
c = {'c', 'm', 'r'};

for i = 1:length(params)
    variables = original_var;
    idx_removed = find(ismember(variables, params{i}));

    if lam_sig == 1 && i == 3
        sig_values = params_values(i, :) .* tot0_value;
        idx_removedsig = find(ismember(variables, sig));
        idx_removed = [idx_removed, idx_removedsig];

        var = variables; val = values;
        var(idx_removed) = []; val(idx_removed) = [];
        y1_expr_subs = subs(expressions{1}, var, val);

        for j = 1:length(params_values(i, :))
            p_val = params_values(i, j);
            s_val = sig_values(j);
            y1_ss_param(i, j) = double(subs(y1_expr_subs, [params{i}, sig], [p_val, s_val]));
        end
    else
        var = variables; val = values;
        var(idx_removed) = []; val(idx_removed) = [];
        y1result = subs(expressions{1}, var, val);

        for j = 1:length(params_values(i, :))
            y1_ss_param(i, j) = double(subs(y1result, params{i}, params_values(i, j)));
        end
    end
end

% Plotting
for i = 1:length(params)
    subplot(length(params), 1, i)
    x = params_values(i, :);
    y = y1_ss_param(i, :);
    if length(params)==3
        Y_image = repmat(y, 1, length(x));

        % Set threshold logic
        if strcmp(labels{1}, 'Native [conc. (uM)]')
            colormap(flipud(parula));
            minthreshold = threshold;
            maxthreshold = max(y);
        else
            colormap(parula);
            minthreshold = min(y);
            maxthreshold = threshold;
        end
    

        % Mask out-of-range values in Y_image
        Y_image(Y_image < minthreshold | Y_image > maxthreshold) = NaN;

        % Create y_display based on y range direction
        if y(1) > y(end)
            y_display = linspace(max(y) + 1, min(y) - 1, size(Y_image, 1));
        else
            y_display = linspace(min(y) - 1, max(y) + 1, size(Y_image, 1));
        end

        % Display image
        imagesc(x, y_display, Y_image);
        set(gca, 'YDir', 'normal');
        clim([minthreshold, maxthreshold]);
        colorbar;
        hold on;

        % Mask for axis limits
        mask = y >= minthreshold & y <= maxthreshold;
        x_visible = x(mask);
        y_visible = y(mask);

        if ~isempty(x_visible)
            xmin = min(x_visible); xmax = max(x_visible);
            ymin = min(y_visible); ymax = max(y_visible);
            axis([xmin xmax ymin ymax]);
        end
     end

    % Overlay curve
    plot(x, y, c{i}, 'LineWidth', 2);
    xlabel(labels{1 + i});
    ylabel(labels{1});
    set(gca, 'XScale', 'log');

    % Formatting
    ax = gca;
    ax.YAxis.Exponent = 0;
    ax.YTickLabelMode = 'auto';
    ax.YMinorTick = 'on';
    ax.MinorGridLineStyle = ':';
    title([labels{1} ' vs ' labels{1 + i}]);
    grid on;
    hold off;
end

sgtitle(labels{end});
saveas(gcf, [labels{end} '.png']);

[Kaylie]

Matlab answers cut off my question part which is that, how could I fix and change my code to work when the function is increasing and how to fix the artifact of the current color map. Thank you!

[William Rose]

@Kaylie,

You provided a function. Please include a script (the simplest possible) that calls the function and demonstrates its use. If you need to attach some data to use as argument for the function, you can put those variables into a .mat file and post that too. Thank you.

Answer 1

[William Rose]

@Kaylie,

Here is a script that makes six curves that are similar to the six curves in your figures. It plots each curve with a colored background that corresponds to the y-values of the curve. I think that is what you wanted. Detailed comments in the script explain how it works. Modify the script to plot your data. The script makes the figure below. Compare it to the figures you posted.